There are applications that require multiple switches that can be individually operated by manipulation of a single actuator. One example is in a portable telephone with a screen that displays telephone numbers, and switches that allow the numbers to scroll up or down. When the desired name and telephone number are displayed, a person operates a validation switch to initiate a call. Further advances allow a user to select additional functions by incorporating additional switches that can be operated by the same actuator. The entire switch arrangement may lie in a body having a width and length of 6 millimeters each.
The above types of switch arrangements with three or five switches can be implemented by an actuator that tilts about two horizontal axes to close one of four select switches, and that can be depressed to close a fifth validation switch. One arrangement involves mounting four pairs of switch elements on a frame with one element of each pair deflected against the other element of the pair when the actuator is tilted in a particular direction. This involves eight contacts, in addition to two contacts for the validation switch. The presence of ten contacts that each must be connected to a trace on the circuit board on which the switch lies, results in complication and extra expense, as well as extra space required on the circuit board. In portable telephones, space is at a premium, and a reduction in the required space taken by the switch arrangement would be of value.
In accordance with one embodiment of the present invention, an electrical switch arrangement is provided with multiple switches, especially with three or five switches, in which a single validation switch is operated by depressing an actuator along a vertical axis, and one of a plurality of selector switches is operated by tilting the actuator about a selected horizontal axis. The switch arrangement includes a center tripper of the dome type, with a periphery engaged with an outer contact and a center that can be snapped down by depressing the actuator. The arrangement also includes a selection tripper lying on top of the center tripper and having radiating branches. The actuator has feet that each lies over one of the branches.
When the actuator is tilted, one of its feet presses a corresponding selection tripper branch against a selection contact. Current then flows between the selection contact, through the selection tripper, and through the center tripper to the periphery of the center tripper that continually engages an outer contact. In an arrangement with five switches, only six contact tails are required to be soldered to traces on a circuit board.
The actuator includes a socket that forms the feet that depress the selection tripper branches and that forms a vertical passage that slideably receives a pusher. The pusher can be separately depressed to reliably operate the validation switch, without depressing the socket whose feet operate the selection switches.
The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when used in conjunction with the accompanying drawings.